KETTLEBELLS are some of today’s hottest equipment in physical fitness training and athletic conditioning. Proponents claim that kettlebells can increase power, strength, and endurance, and can even help you reduce fat. With all that bang for your buck, pairing kettlebell training with the sport of boxing seems like a perfect match. Maybe, maybe not. Let’s look beyond the hype.

Kettlebells are available in many styles and types of material, but the basic design consists of a U-shaped handle attached to a single round weight. The early kettlebells looked like cannonballs, and the handles were extremely thick so they could be anchored securely to the weight. In contrast, a dumbbell has two weights attached to a single handle.

The advantage of having a handle attached far from the center of mass of the bell is that it makes it easy to perform numerous swinging movements, such as kettlebell swings. Yes, swings can be performed with dumbbells, but they are easier with a kettlebell. The U-shaped handle also enables the user to perform many release exercises; not surprisingly, kettlebells are popular with throwers in track and field events such as discus and hammer throw.

Here’s a bit of history: A description of a kettlebell appeared in a Russian dictionary published in 1704; the Russian word for kettlebell is girya. However, the first uses of kettlebells were as counterweights in the marketplace. The Russians eventually figured out these weights could be used as exercise tools, and soon they became popular among trainers of military personnel and track and field athletes. Kettlebells were often used as conditioning tools by Olympic-style weightlifters, including the first man to clean and jerk 500 pounds, Vasily Alexeyev.

Although primarily used as a conditioning method, kettlebells are often used in many fitness challenge competitions, especially in the United States. However, it appears the first pure kettlebell competition took place in 1948 in Russia, which led to a national championship in 1985 called the USSR National Girevoy Sport Championship.

This national competition consisted of the clean and jerk and the one-arm power snatch, performed for repetitions. The weight of the kettlebell that an athlete would use depended upon the classification the athlete competed in: 16, 24, or 32 kilos (35, 52, or 70 lbs). By performing a specific number of repetitions with specific weights, an athlete would earn a national ranking in girevoy sport.

For energy system conditioning and fat loss, kettlebell training has value. In a study published in the January/February 2010 issue of ACE FitnessMatters, researchers at the University of Wisconsin measured the caloric expenditure of 10 subjects who performed a 20-minute workout using a snatch exercise with kettlebells. Lead researcher John Porcari, Ph.D., determined that the workout burned an average of 272 calories, which is a rate equivalent to running a mile at a six-minute pace. Said Porcari, “The only thing I could find that burns that many calories is cross-country skiing uphill at a fast pace.” As such, for those who have a short time, kettlebell training can be a way to burn a lot of calories in a short period.

Just as there are studies supporting the value of kettlebell training, there are others that expose its weaknesses. For example, in a 10-week study on the effects of kettlebell training published in the February 2013 Journal of Strength and Conditioning Research, 23 subjects performed two kettlebell workouts, each lasting one hour, twice a week for 10 weeks. This training was preceded by two orientation sessions (one-hour each) by a certified kettlebell instructor. The researchers measured the height of the subjects’ vertical jumps before and after the study. Vertical jumping ability indicates how quickly an athlete can apply force, an important athletic quality. Researchers reported that kettlebell training did not produce a significant increase in vertical jumping ability.

To enhance vertical jumping ability, squats and plyometrics have proven particularly effective. A study published in the Journal of Applied Sports Science Research in January/February 1992 found that after six weeks a group performing squats and plyos increased their vertical jump an average of 4.2 inches (10.67 centimeters). The training was preceded by two workouts to learn the exercises. The workouts were performed twice a week. A group performing squats increased their vertical jumps by 3.30 inches (8.38 centimeters), a group performing plyos improved by 3.81, and a group performing both improved by 4.20 inches (10.67 centimeters).

So we know that after six weeks you can get good results with squats or plyometrics, or exceptional results by performing both. In contrast, kettlebell training for 10 weeks for a total of 20 hours produced no results whatsoever.

That’s a glance at the research. Here is what my experience tells me.

First, virtually any exercise you can perform with a kettlebell you can perform with a dumbbell. Outfitting a gym with a complete set of dumbbells is expensive, especially when purchasing the heavier dumbbells. Also, many gyms are short on space, and having to outfit a gym with complete sets of dumbbells and kettlebells is simply not an option.

Most kettlebells do not have revolving handles – and the styles that do are very, very expensive. The rigid handle design places extreme stress on the wrists and elbows. Also, exceptional technique is necessary; otherwise, the bells will bang against the forearms and cause bruising. In the four research studies I found on boxing injuries sustained between 1984 and 1990, researchers reported that the most prevalent upper body injuries were those to the wrists and hands.

Finally, consider that kettlebell swings can place a high level of stress on the spine. Although some individuals claim they can resolve or prevent lower back pain, research has found that standard exercises such as the kettlebell swing may cause back pain. One study on this exercise, headed by noted back pain researcher Stuart McGill, was published in the January 2012 issue of the Journal of Strength and Conditioning Research. McGill and his col- leagues found that the kettlebell swing places a high level of shearing forces on the L4-L5 vertebrae, even when compared to traditional strength training exercises such as squats and deadlifts.

Kettlebells have a long history in sports and have reemerged as popular equipment in the fitness industry. They certainly can improve endurance and are great calorie-burners, and because they have a strength training effect they have the potential to deliver a lot of value in a single exercise tool. However, the risks are substantial. Before you decide to add kettlebells to your program, carefully assess the risks versus the benefits.

His book about strength and conditioning for fighters, The Klatten Power Boxing System, will be available in April from Amazon.

As a strength coach for boxing, Moritz Klatten has trained three Olympic champions, four amateur world champions, and five professional world champions, including Yuriorikis Gamboa, Juan Carlos Gómezs, Herbie Hide, and Jack Culcay. Among the boxing coaches he has worked with are Ismael Salas, Orlando Cuellar, Fritz Sdunek, Michael Timm, Freddie Roach, Joey Gamache and Jimmy Montoya. Coach Klatten is also an accomplished strength coach for football and has attracted an international clientele that includes Zlatko Junuzović, Werder Bremen; Tolgay Arslan, Beşiktaş; and Piotr Trochowski, Augsburg. Coach Klatten works primarily out of Champ Performance, his own gym in Hamburg, Germany, where he offers strength coaching internships and operates a satellite training service to work with athletes worldwide. He can be reached at klatten@champperformance.de